The present invention relates to various components for use in an optical fibre network, in particular for splicing, terminating and splitting.
Optical fibres are in general very small, brittle and therefore easily damaged and as a result great care must be taken in their installation and use. In order to avoid damage and light loss, a fibre must not be bent excessively and it must not be subject to unfavourable environmental conditions. As is well know, each fibre has a so-called critical bend radius below which light will be lost from the fibre. Therefore, an optical fibre system must be so configured that none of its fibres is bent at a bend radius below this critical value. Also, fibres must not be even temporarily bent during installation below a smaller bend radius at which permanent damage will occur. These requirements put constraints on the design of components for optical fibre networks.
The components in an optical fibre system are required to organize cables and their component optical fibres at, for example, cable terminations, cable splices and fibre splitters. This involves careful fibre routing, for example to allow easy access to each of many fibre splices, and storage of spare lengths of fibre.
Many proposals have been made to satisfy these requirements. For example, U.S. Pat. No. 4,840,449 (AT&T) discloses an optical fibre organizer and splicing arrangement that permits storage of variable lengths of surplus fibre. The organizer has a pair of separated cylinders extending from a first rectangular section of a base plate and a splice tray having opposite entrance sides for optical fibre in a second rectangular section. The surplus fibre is directed around one or both cylinders and underneath the splicing tray through a plurality of different length passageways so that the varying lengths of optical fibre are stored. Clockwise, counter-clockwise and FIG. 8 loops are used so that each optical fibre end is directed to a predetermined entrance side of the splicing tray without violating the fibre bend radius restriction.
U.S. Pat. No. 4,627,686 (Siecor) discloses a splicing tray for optical fibres and optical fibre cables comprising three elements: a base, a number of optical fibre storage means associated with the base and an optical fibre receiving means attached to the base. Around the periphery of the base is a plurality of upstanding sidewall members, the terminal portion of which is curved inwardly towards the centre of the base.